WebGL Lab.
// title: Noise

#ifdef GL_ES
precision mediump float;
#endif

uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;

float random(vec2 st){
  return fract(sin(dot(st.xy,u_mouse+vec2(999.,999.)))*40000.);
}

void main(){
  vec2 st=gl_FragCoord.xy/u_resolution;
  
  float rnd=random(st);
  
  gl_FragColor=vec4(vec3(rnd),1.);
}